- Tivantinib is metabolized by CYP2C19, and to a lesser extent cytochrome P450, family 3, subfamily A, polypeptide 4 (CYP3A4); the metabolism and consequently overall pharmacokinetics of tivantinib could be altered by inhibitors and/or inducers or other substrates of CYP2C19 and CYP3A4; while inhibitors/inducers of these cytochrome P450 isoenzymes are not specifically excluded, investigators should be aware that tivantinib exposure may be altered by the concomitant administration of these drugs; as part of the enrollment/informed consent procedures, the patient will be counseled on the risk of interactions with other agents, and what to do if new medications need to be prescribed or if the patient is considering a new over-the-counter medicine or herbal product